JPH0255408A - Manufacture of dielectric filter - Google Patents

Abstract

PURPOSE:To simplify the manufacture process by forming throughholes resulting in forming plural resonator units to a dielectric block, forming other throughhole between them, and immersing the block to an electrode paste so as to grind one end of the throughholes of the block. CONSTITUTION:Throughholes 11 are provided at a prescribed pitch to a rectangular dielectric block 10. A recessed part 17 is provided in a direction at a right angle to a line segment tying the throughholes 11 and a throughhole 15 whose cross section is rectangular is provided to the bottom of the recessed part 17 in the same direction as that of the throughholes 11. Then the block 10 is dipped in the electrode paste to form a conductive film on the whole surface. After the conductor film is dried and basked, the upper face 12 with the recessed part 17 formed thereupon is ground to decide the length of the resonator unit to be a size in matching with a prescribed resonance frequency. The upper face 12 is formed to be an open end face by the grinding and the rear side 12' is formed to be a short-circuit end face. Moreover, the conductor film of the throughholes 11 becomes the inner conductor and the conductor film on the side face 13 becomes an outer conductor. The conductor film in the throughhole 15 is short-circuited by the conductor film of the bottom face and the recessed part 17. Thus, the manufacture process is simplified and the adjustment of the resonator is facilitated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a dielectric filter that couples resonators by capacitance, and particularly relates to a method for manufacturing a dielectric filter using a dielectric block formed with an integral film. The present invention relates to a method for manufacturing a filter.

[Prior art]

Filters using dielectric band resonators are now being used in various fields as filters for microwave bands, duplexers, and the like.

In the past, filters in which cylindrical dielectric coaxial TEM resonators were coupled by capacitance were common, but recently dielectric filters in which multiple resonator units were formed within a dielectric block have come into use. There is.

FIG. 4 is a perspective view showing such a block-shaped dielectric filter, in which a through hole 41 is formed in a dielectric block 40, and a conductive film is formed in the through hole 41 to serve as an inner conductor. A conductive film 43 is formed on the surface of the dielectric block 40 except for the open end surface 42, and serves as an external conductor. As a result, two resonator units are integrally formed. Note that a coupling hole 45 is formed between the resonator units, and no body film is formed inside this coupling hole 45.

In such a dielectric filter, the resonator units are capacitively and magnetically coupled. Therefore, the characteristics of each resonator unit cannot be adjusted individually, making it extremely difficult to adjust the frequency characteristics. Furthermore, it is necessary to change the mold for each filter with different characteristics, and furthermore, since a conductive film is not formed in the coupling hole, there are major problems in terms of man-hours and costs. When using individual resonators, there are problems such as assembly man-hours, strength, and stability.

〔assignment〕

The present invention aims to provide an integrated dielectric filter that eliminates magnetic coupling. This makes the adjustment of individual resonant units and couplings easy to use.

Another object of the present invention is to obtain a dielectric filter that is easy to assemble and has high reliability.

Furthermore, it is an attempt to obtain a dielectric filter with such excellent characteristics with fewer man-hours.

[Failure to solve the problem]

The present invention solves the above problems by simultaneously forming a conductive film not only on the surface of the dielectric block and the inner conductor but also in the through holes formed between the resonator units.

That is, in a method for manufacturing a dielectric filter including a plurality of resonator units in a dielectric block and a through hole in which a conductive film is formed between the resonator units, an inner conductor of the resonator unit is formed. A dielectric block having a through hole formed between the resonator units and the through hole formed between the resonator units is immersed in electrode paste 1- or subjected to plating treatment to form a conductive film on the surface and inside each through hole. The feature is that the surface of the dielectric block on one end side of the transfer through hole is polished.

Further, a recess is formed on the surface of the dielectric block in contact with the through hole between the resonator units, and the conductor film in the recess remains after polishing to short-circuit the conductor film in the through hole.

[Effect]

A through hole is formed between the resonator units, and when a conductor film is formed in the through hole and both ends are short-circuited, magnetic coupling between the resonator units is interrupted. For this purpose, the conductor film of the through hole and the outer conductor are electrically connected, and a conductor film that is electrically conductive with the conductor film of the through hole is formed on the open end surface and connected to the outer conductor.
A short circuit is formed as a whole.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, through holes 11 are formed at predetermined intervals in a rectangular parallelepiped dielectric block 10, in which inner conductors of a resonator unit are formed. A through hole 15 extending in the same direction as the through hole 11 is formed between the resonator units. Note that it is preferable that the through hole 15 has a rectangular cross section so that the width becomes wider in the direction perpendicular to the direction in which the resonator units are connected as shown in the figure. Further, on the surface of the dielectric block 10 in the portion where the through hole 45 is located,
A recess 17 is formed across this surface.

Next, as shown in FIG. 2, a conductive film is formed on the entire surface of the dielectric block 10. A conductor film serving as an inner conductor is disposed inside the through hole 11, and an electrode film 1 serving as an outer conductor is disposed on the outer peripheral surface of the dielectric block.
3 are formed respectively. Further, a conductive film is similarly formed inside the through hole 15.

As described in ``-'', since the conductive film is formed on the outer peripheral surface, inside the through hole, and on the entire dielectric block, there is no need to keep the coupling hole portion cold as in the conventional method. Therefore, the entire dielectric block can be immersed in a conductive paste such as silver or in a plating solution such as copper. Therefore, the number of steps for forming the conductor film can be extremely reduced.

The conductor film is subjected to treatments such as drying and baking. Thereafter, as shown in FIG. 3, the surface on which the recesses 17 are formed is polished. By this polishing, the length of the resonator unit is adjusted to match a predetermined resonance frequency. By polishing, the dielectric material is exposed on this surface, and this becomes an open end surface. The surface on the back side of this surface is left with the conductor film formed thereon, and becomes a short-circuited end surface.

The conductor film formed in the recess 17 remains even after polishing is completed. Therefore, the depth of the recess must be greater than the polished dimension of the resonator unit. The conductor film remaining in this recess is electrically connected to the conductor film in the through hole 15 and also to the outer conductor 13. In other words, both ends of the conductor film within the through hole 15 are short-circuited.

A dielectric filter can be obtained by examining the input/output coupling means of the dielectric block manufactured in this manner. The conductive film between the resonator units blocks magnetic coupling between the resonator units.

Therefore, capacitive coupling is the only element of coupling between resonators.

〔effect〕

According to the present invention, a professional dielectric filter in which magnetic coupling is cut off can be obtained. As a result, a dielectric filter is realized in which adjustment of individual resonators and coupling can be easily adjusted.

Further, since the formation of the conductor film for blocking can be performed simultaneously with the formation of the inner conductor and the outer conductor, the manufacturing process can be simplified.

Furthermore, it is possible to obtain a block-type filter with magnetic coupling cut off using an integral film, which is advantageous in terms of assembly, reliability, and the like.

[Brief explanation of the drawing]

1 to 3 are perspective views showing an embodiment of the present invention, and FIG. 4 is a perspective view showing an example of a conventional dielectric filter. 10...Dielectric pro-tsuku 11...Through hole 15...Through hole 17...Four parts

Claims (6)

[Claims] (1) In a method for manufacturing a dielectric filter including a plurality of resonator units in a dielectric block and a through hole in which a conductive film is formed between the resonator units, the inner conductor of the resonator unit is formed. a dielectric block having a through hole formed between the resonator unit and the resonator unit, is immersed in electrode paste to form a conductive film on the surface and inside the through hole;
A method for manufacturing a dielectric filter, comprising: thereafter polishing the surface of the dielectric block on one end side of the through hole. (2) In a method for manufacturing a dielectric filter including a plurality of resonator units in a dielectric block and a through hole in which a conductor film is formed between the resonator units, the inner conductor of the resonator unit is formed. A dielectric block having a through hole formed between the resonator unit and a through hole formed between the resonator units is plated to form a conductive film on the surface and inside the through hole, and then the dielectric block at one end of the through hole is plated. A method for manufacturing a dielectric filter, which comprises polishing the surface of a block. (3) The dielectric filter according to claim 1 or 2, wherein the conductor film is formed after forming a recess crossing the surface of the dielectric block in contact with at least one end side of the through hole between the resonator units. manufacturing method. (4) The surface of the dielectric block in which the recess is formed is polished to expose the dielectric to form an open end surface.
A method for manufacturing a dielectric filter as described in . (5) polishing the surface of the dielectric block in which the recess is formed to expose the dielectric and form an open end surface;
4. The method for manufacturing a dielectric filter according to claim 3, wherein a conductive film is left on the surface of the recess. (6) polishing the surface of the dielectric block in which the recess is formed to expose the dielectric and form an open end surface;
4. The method of manufacturing a dielectric filter according to claim 3, wherein a conductive film electrically connected to the conductive film in the through hole and the outer conductor is left on the surface of the recess.